Distribution and abundance of bee forage flora across an agricultural landscape – railway embankments vs. road verges

In this study, we evaluated if railway embankments and road verges create refuge habitats for bee flora across agricultural landscape. The survey was conducted in 2009–2012, in the Lublin Province, SE Poland. Data on the bee forage flora were obtained while making floristic charts along 60 transect plots × 300 m, with a total length of 18 000 m, for each type of linear structure. Forage bee flora was compared with respect to species richness, diversity, and evenness indices. The canonical correspondence analysis (CCA) was used to characterize relationship between species composition and environmental variables. The bee forage species richness and abundance were significantly greater on railway embankments than on road verges. The composition of species varied considerably; the number of bee forage species common to both habitats was only approximately 38% in entire data set. Most good-value bee forage species were recorded along the embankments of railways with an intermediate traffic volume. Bee forage species diversity benefits from the location of habitat elements (forests or meadows), primarily if the distance is <50 m. The lack of dense patches of valuable bee forage species in the road verges was related to the high density of non-nectariferous graminoids. Our results demonstrate how the value of man-made areas in an agricultural ecosystem can vary with respect to floral resources across the landscape, suggesting that it is inappropriate to generalize about agricultural systems as a whole without first addressing differences among habitats

Floral biology of Senecio macrophyllus M. BIEB. (Asteraceae), a rare Central European steppe plant

Knowledge of the flowering phase and plant pollination ecology is very important for understanding the life history of long-lived perennials. In the case of rare species, the information may have implications for conservation practices. Our studies on flower morphology and blooming biology of the vulnerable plant Senecio macrophyllus M. BIEB. were conducted in situ (flowering, activity of insect visitors) in the largest population in SE Poland and in laboratory (light and scanning electron microscopy). The disc florets open diurnally with most intensive anthesis in the early afternoon and attract insect visitors with nectar and pollen. In highly protandrous disc florets, pollen viability decreases in time, whereas stigma receptivity increases. The upper part of the pistil forms a brush-like pollen presenter, covered with unicellular trichomes with chromoplasts. Pollen presentation lasts 4–11 hours per floret, and 8 days in a single head, the main function of which is to extend the availability of male gamets for reproduction. The number of florets per head, the head size, and the number of pollen grains produced per anther, and the pollen grain viability differed significantly between microsites. The finding indicates that, apart from the biotic factors, abiotic conditions may considerably influence generative reproduction of the species. In the study area, the principal visitors of S. macrophyllus flowers were Hymenoptera, with predominance of Apis mellifera (53.4% of visits). The remarkable share of butterflies (13.9%) recognized as the long-distance moving insects may improve the genetic variability of individuals within a fragmented population. A more detailed study is necessary to explain the role of insect visitors in effective pollination and in gene transfer between patches. The assessment of optimal conditions for the generative reproduction is fundamental for the in situ conservation of this rare species

Morphology of Anemone sylvestris L. flower (Ranunculaceae)

During the monitoring of populations of Anemone sylvestris L. (Ranunculaceae), a protected species in Poland, we found that the seed set is impaired. The flower is considered an adaptation that has coevolved to achieve effective pollination and successful fertilization. Therefore we have focused on the morphological and anatomical characteristics of the flowers of A. sylvestris L. as a prelude to the study of the species’ pollination biology and plant breeding system. The large size of the flower (50.6 ± 16.4 mm in dimensions) and its bowl shape fulfil both the biotic pollination syndrome and the aerodynamic requirements for pollen dispersal and capture. The opening and closing of the perianth provide a shelter for beetles. The odourless perianth, absence of nectar, scarcity of pollen (approximately 200 000 pollen grains per flower) and its traits – small size (axis P = 18.52 ± 1.0 μm; E = 16.59 ± 0.9 μm), lack of balsam on the exine surface, starch accumulation in more than 95% of pollen grains correspond to the specialization in anemophily. The stigma is papillous, the dense hairs are situated between single carpels indicating adaptation to capturing dry pollen and specialization in the wind pollination syndrome. The flower of A. sylvestris is an example for an intermediate form between entomophily and anemophily, i.e. a secondary and more advanced feature among Ranunculaceae

Pollination and floral biology of Adonis vernalis L. (Ranunculaceae) – a case study of threatened species

Although the knowledge of pollination systems of rare and threatened species is one of the principles for development of optimal conservation and management strategies, the data about their pollination requirements are scarce or incomplete. Different problems are listed (xerothermic habitat disappearance, overgrowing of patches, plant biology i.e., slow plant growth, problems with seed germination) among the possible causes of Adonis vernalis being threatened, but until now no consideration was given to the flowering biology and pollination. The observations of flowering biology of A. vernalis (Ranunculaceae), a clonal species, were conducted in an out-of-compact-range population, in the Lublin Upland, Poland (51°18'55" N, 22°38'21" E), in 2011–2013. The reproductive potential of A. vernalis is related to the population age structure, pollination syndrome, and breeding system. The flowers exhibit incomplete protogyny. The dichogamy function is supported by different (biological, morphological) mechanisms. Stigma receptivity occurred about one day before anthers started shedding self-pollen, and pollen viability was increasing gradually during the flower life-span (66.3% in distal anthers vs. 77.3% in proximal). The decrease in pollen production and in pollen viability coincided with the lowest degree of seed set, irrespective of the pollination treatment. Pollen vectors are necessary for efficient pollination, as the proportion of pistils setting fruits after open pollination (41–82.1%) was significantly higher compared to spontaneous self-pollination (only 5.5–12.3%). The pollination requirements together with pollen/ovule ratio (P/O = 501) indicate a facultative xenogamous breeding system in A. vernalis. Therefore, in the conditions of the global lack of pollinators, improper pollination may weaken the population by leading to a decrease in the proportion of recombinants, and in addition to other factors, may accelerate extinction of small A. vernalis populations

Nectar and pollen production of Helianthus tuberosus L. – an exotic plant with invasiveness potential

In Central Europe, Helianthus tuberosus L. is a late summer/autumn bloomer (August/November). The disc florets produce both nectar and pollen. Floral reward is available in male-phase flowers (pollen and nectar) and in female-phase flowers (nectar). The floral reward is attractive to a variety of insect visitors (honey bees, wasps, flies and butterflies). The season of blooming as well as the total sugar yield (25.4 – 47.4 kg ha–1) and pollen yield (57.8 – 212.7 kg ha–1) indicate that H. tuberosus is important in the enhancement of food resources for pollinators. The generative reproduction in H. tuberosus is impaired (the species does not set seeds/fruits). However, due to its attractiveness for a variety of pollinators in both rural and urban areas, the spread of H. tuberosus should be monitored. Moreover, its propagation needs to be attended with restrictions

Factors determining the diurnal dynamics of blooming of chosen plant species

The paper attempts to synthesize the determinants which may influence the diurnal rhythm of blooming. Additionally, I tried to explore and bring together topics that concern blooming and have always been considered separately because of their origin in different disciplines. The following species were included: Hydrangea arborescens L. subsp. discolor (Raf.), H. paniculata Sieb., Viburnum opulus L., Chaenomeles japonica Lindl., Knautia arvensis L., Adonis vernalis L., Aster saggitifolius Willd., Taraxacum officinale L. Chelidonium majus L. The taxons were observed in Lublin (51008' - 51018' N and 21027' - 21041' E) in the years 2001-2007. The blooming of species was determined at least for two vegetation seasons. During observations all flowers developed in one-hour intervals were counted. The diurnal dynamics of blooming differs among species and is modified by different endogenous and exogenous factors. The endogenous determinants of diurnal dynamics of blooming are morphological diversity of flowers (fertility or sterility) within species or heterostyly. The different pattern of blooming succour different mechanisms which prevent self-pollination (Chaenomeles japonica Lindl., Knautia arvensis L.). The abiotic factors, such as day length and temperature during the vegetation season, influence the change in the process of diurnal dynamics of blooming (e. g. Taraxacum officinale, Chelidonium majus)

The impact of spatio-temporal changes in flora attributes and pollen availability on insect visitors in Lamiaceae species - Online supplement

There is growing evidence that food, in particular pollen, limitation is the strongest factor in pollinator decline. We have considered the potential effects of diversity in plant-community attributes as well as variations in the pollen and energy amount on the abundance and frequency of insect visitors to the Lamiaceae species Salvia pratensis L., S. verticillata L., Thymus serpyllum L., Betonica officinalis L. syn. Stachys officinalis (L.) Trevis., and Origanum vulgare L. The species were grown in two different habitat types (dry grassland vs. railway embankment) in the Lublin Upland, Poland. We found significant inter-species, inter-habitat, and inter-year disparities in the pollen mass and total energy amount per unit area. Canonical correspondence analysis (CCA) revealed that the blossom cover, species richness, and diversity noted at the plant community level significantly influenced the distribution of insect visitors to Lamiaceae species. The pollen caloric value and pollen abundance (but not the protein content in the pollen) had a considerable impact on the abundance and frequency of honeybees, bumblebees, and solitary bees in Lamiaceae flowers. Butterflies, beetles and flies did not respond to these factors. The model including all variables explained 66.4% of the observed variance. The studied Lamiaceae species, due to abundant flowering and good pollen nutritional value should be considered in the protocols to improve food resources, especially for social bees; however, disparities in pollen quantity and energy amount should not be ignored

Entwicklungsperspektiven des russischen Parteiensystems

Im Sommer 2005 hat das "Zentrum für politische Technologien" im Auftrag der Friedrich-Ebert-Stiftung eine Studie über die Entwicklung des russischen Parteiensystems erarbeitet. Die Autoren interpretieren die russische Situation als "mexikanisches Modell", in dem die "Partei der Macht" zwar die absolute Mehrheit hat, die anderen Parteien aber von ihr unabhängig sind und Kritik an ihr üben. Die in den letzten Jahren verabschiedeten Änderungen der Regeln über den Zugang auf den "politischen Markt" verschärfen die Defizite des russischen Parteiensystems: eine begrenzte institutionelle Bedeutung in der Politik, inadäquate Artikulation der gesellschaftlichen Interessen und als Folge davon ein geringes Vertrauen der Bevölkerung gegenüber den Parteien, die sich angesichts der Neuerungen des Vertretungsorgans der Macht (und folglich auch der Parteien) noch weiter voneinander entfernen könnten. Die Herausbildung einer "klassischen Demokratie" in Russland ist in naher Zukunft höchst unwahrscheinlich. Der Weg hin zu einem vollwertigen, konsolidierten Parteiensystem in Russland wird sehr langwierig und schwierig sein

Floral phenology and pollen production in the five nocturnal Oenothera species (Onagraceae)

Blooming phenology and pollen production in the five Oenothera species were investigated during the period of 2013–2015 in the Lublin area, SE Poland. The blooming period was relatively long, and flowering usually started in the middle or late June and lasted until late July or the middle of August. The Oenothera species studied exhibited nocturnal anthesis, i.e., the flowers opened in the late evening and lasted overnight until the early morning hours. Plants developed a great number of flowers per individual and per unit area (on average, 158 and 4,136, respectively), and this feature appeared to be species-specific. It was demonstrated that the blooming phase had an impact on the mass of anthers and pollen produced per flower in all Oenothera species. In general, the greatest mass of anthers and pollen was observed at the beginning of blooming, and with the progress of flowering, the values decreased. However, statistical differences were found for O. flaemingina, O. paradoxa, and O. rubricaulis. The mass of pollen produced per unit area was also a species-specific characteristic and was related to the abundance of flowering. The greatest amount of pollen was produced by O. flaemingina (30.6 g m−2), which was almost three times more than that produced by O. rubricaulis (10.9 g m−2). The protein content of pollen grains was relatively low and on average amounted to 15.4%. The Oenothera species examined in this work may be considered valuable pollen yielding plants. Nevertheless, given the invasive potential of species from subsect. Oenothera, precautions are suggested during cultivation and/or planting these taxa in bee pastures, in order to prevent uncontrolled spread into new areas